Re:

If you and your apartment mates share a router (then connect to the external wall), it is possible to control the network transfer rate for BitTorrent, edonkey and any other P2P programs. If the router get Linux installed, you can iptables to do that. It might be complicated if you are a Windoze-only guy. OpenSource is great!

If all the people connect to the internet through the alreay exist sockets, your router is controlled by the ISP. You can try to contact them. Nowadays most ISP use linux to provide internet connection for custumers. But they may not do as you request.

In a summary, technically it is possible to control the transfer rate for a given programs (based on port), but it might not be practical.